921921820 has 12 divisors (see below), whose sum is σ = 1936035864. Its totient is φ = 368768720.

The previous prime is 921921817. The next prime is 921921823. The reversal of 921921820 is 28129129.

It is an interprime number because it is at equal distance from previous prime (921921817) and next prime (921921823).

It is a super-2 number, since 2×921921820² = 1699879684384224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921921823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23048026 + ... + 23048065.

It is an arithmetic number, because the mean of its divisors is an integer number (161336322).

Almost surely, 2^921921820 is an apocalyptic number.

It is an amenable number.

921921820 is an abundant number, since it is smaller than the sum of its proper divisors (1014114044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

921921820 is a wasteful number, since it uses less digits than its factorization.

921921820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46096100 (or 46096098 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 921921820 is about 30363.1655134968. The cubic root of 921921820 is about 973.2655800819.

The spelling of 921921820 in words is "nine hundred twenty-one million, nine hundred twenty-one thousand, eight hundred twenty".